Denison Mines Completes Summer Exploration Activities

TORONTO, ON - Denison Mines Corp. reported the completion of its summer 2015 exploration activities. The program was highlighted by the expansion of the Gryphon Zone of uranium mineralization on the Wheeler River property, and the discovery of a new zone of uranium mineralization on the Murphy Lake property.

A total of 24,468 meters of drilling was completed in 34 drill holes during the summer program at Denison's 60% owned Wheeler River project. Seven of the drill holes were designed to complete the 50 meter x 50 meter spaced drill pattern at Gryphon and outline the extent of the mineralization in the down-dip and down-plunge directions. The best result was in drill hole WR-604, for which chemical assay data is now available. WR-604 intersected 6.3% U3O8 over 5.5 meters (779.0 to 784.5m), followed by 11.6% U3O8 over 1.0 meters (790.0 to 791.0m) - extending the zone of mineralization approximately 50 meters in the down-dip direction. The Gryphon Zone of mineralization is now approximately 450 meters long in the down-plunge direction and 80 meters wide in the across-plunge direction. Thickness is variable due to the stacked nature of the lenses.

With the receipt of the final chemical assays from the drilling completed at the Gryphon Zone, the Company is working towards the completion of updated mineral resource estimates for the Wheeler River property before the end of 2015. The updated technical report, which is being prepared in accordance with National Instrument 43-101, will include a mineral resource estimate at Gryphon, in addition to the Phoenix Deposit, which is located roughly 3 kilometers to the southwest of Gryphon. The Phoenix Deposit is currently estimated to contain an indicated mineral resource of 70.2M lbs U3O8 at a grade of 19.13% and an inferred mineral resource of 1.1M lbs U3O8 at a grade of 5.8%.

Twenty additional drill holes were completed in the general K North area surrounding the Gryphon Zone, to evaluate a variety of targets and identify additional mineralization. The best result from these targets was in drill hole WR-612, located 200 meters south of the unconformity mineralization identified on the WR-595/597 section during the winter 2015 exploration program. WR-612 intersected 2.4% U3O8 over 2.5 meters, approximately 25 meters below the unconformity.